Depression is a state of low mood and aversion to activity or apathy that can affect a person's thoughts, behaviour, feelings and sense of well-being.
People with a depressed mood can feel sad, anxious, empty, hopeless, helpless, worthless, guilty, irritable, angry, ashamed or restless. They may lose interest in activities that were once pleasurable, experience loss of appetite or overeating, have problems concentrating, remembering details or making decisions, experience relationship difficulties and may contemplate, attempt or commit suicide. Insomnia, excessive sleeping, fatigue, aches, pains, digestive problems or reduced energy may also be present.
Depressed mood is a feature of some psychiatric syndromes such as major depressive disorder, but it may also be a normal reaction, as long as it does not persist long term, to life events such as bereavement, a symptom of some bodily ailments or a side effect of some drugs and medical treatments. A DSM diagnosis distinguishes an episode (or ‘state’) of depression from the habitual (or ‘trait’) depressive symptoms someone can experience as part of their personality.
A number of psychiatric syndromes feature depressed mood as a main symptom. The mood disorders are a group of disorders considered to be primary disturbances of mood. These include major depressive disorder (MDD; commonly called major depression or clinical depression) where a person has at least two weeks of depressed mood or a loss of interest or pleasure in nearly all activities; and dysthymia, a state of chronic depressed mood, the symptoms of which do not meet the severity of a major depressive episode. Another mood disorder, bipolar disorder, features one or more episodes of abnormally elevated mood, cognition and energy levels, but may also involve one or more episodes of depression. When the course of depressive episodes follows a seasonal pattern, the disorder (major depressive disorder, bipolar disorder, etc.) may be described as a seasonal affective disorder. Outside the mood disorders: borderline personality disorder often features an extremely intense depressive mood; adjustment disorder with depressed mood is a mood disturbance appearing as a psychological response to an identifiable event or stressor, in which the resulting emotional or behavioral symptoms are significant but do not meet the criteria for a major depressive episode; and posttraumatic stress disorder, an anxiety disorder that sometimes follows trauma, is commonly accompanied by depressed mood. Depression is sometimes associated with substance use disorder. Both legal and illegal drugs can cause substance use disorder.
Questionnaires and checklists such as the Beck Depression Inventory or the Children's Depression Inventory can be used by a mental health provider to help detect, and assess the severity of depression. Semi structured interviews such as the Kiddie Schedule for Affective Disorders and Schizophrenia (KSADS) and the Structured Clinical Interview for DSM-IV (SCID) are used for diagnostic confirmation of depression.
Schizophrenia is a mental disorder characterized by abnormal social behaviour and failure to understand what is real. Common symptoms include false beliefs, unclear or confused thinking, hearing voices that others do not, reduced social engagement and emotional expression, and a lack of motivation. People with schizophrenia often have additional mental health problems such as anxiety disorders, major depressive illness, or substance use disorders. Symptoms typically come on gradually, begin in young adulthood, and last a long time.
Schizophrenia is diagnosed based on criteria in either the American Psychiatric Association's fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM 5), or the World Health Organization's International Statistical Classification of Diseases and Related Health Problems (ICD-10). These criteria use the self-reported experiences of the person and reported abnormalities in behavior, followed by a clinical assessment by a mental health professional. Symptoms associated with schizophrenia occur along a continuum in the population and must reach a certain severity before a diagnosis is made.
Schizophreniform disorder (acute schizophrenic episode) is characterized by the presence of some of the symptoms of schizophrenia including: delusions, hallucinations, disorganised speech, disorganised or catatonic behaviour, and negative symptoms. The disorder—including its prodromal, active, and residual phases—lasts longer than 1 month but less than 6 months. Schizoaffective disorder symptoms can vary greatly from patient to patient. Many patients suffer with problems with mood, daily function or intrusive thoughts. Other symptoms can include elevated, inflated or depressed mood; irritability and poor temper control; changes in appetite, energy and sleep; hallucinations (particularly auditory hallucinations); delusions of reference; paranoia; deteriorating concern with hygiene and disorganised or illogical speech.
Schizoaffective disorder features cycles of severe symptoms followed by improvement. Bipolar I disorder (mania, manic disorder, manicdepressive psychosis) is characterised by mood swings that range from low (feelings of intense depression and despair) to high (feelings of elation, referred to as “mania”) and can be mixed, for example a depressed mood
may be combined with restlessness and overactivity. Often both depressive and manic episodes are experienced.
Bipolar II disorder is characterised by hypomanic episodes as well as at least one major depressive episode. Hypomanic episodes do not go to the extremes of mania (i.e. do not cause social or occupational impairment, and are without psychotic features). Bipolar II is much more difficult to diagnose, since the hypomanic episodes may simply appear as a period of successful high productivity and is reported less frequently than a distressing depression. Psychosis can occur in manic and major depressive episodes, but not in hypomania. For both disorders, there are a number of specifiers that indicate the presentation and course of the disorder, including “chronic”, “rapid cycling”, “catatonic” and “melancholic”
Major depressive disorder with psychotic feature (psychotic depression) is characterised in that a patient in addition to suffering from depressive symptoms also suffers from hallucinations or delusions. These patients often become paranoid and may believe that their thoughts are not their own or that others can ‘hear’ their thoughts.
Delusional disorders (paranoia) are a form of psychosis where the patient has long-lasting paranoid delusions which have no other physical or medical cause. These delusions may also be accompanied by auditory hallucinations.
Shared psychotic disorder (shared paranoia disorder) is a very rare condition in which people close to a mentally ill person share his or her false beliefs (delusions). As an example, a man with schizophrenia may falsely believe that his children are trying to murder him. His wife develops shared psychotic disorder and comes to believe it as well. This disorder usually occurs in long-term relationships and involves two people. However, it can also develop among members of a group, such as within families. It affects women more often than men.
Brief psychotic disorder (other and unspecified reactive psychosis) is characterised by patients who experience an acute psychotic episode lasting longer than one day but less than one month and that may or may not immediately follow an important life stress or a pregnancy (with postpartum onset). This illness usually comes as a surprise as there is no forewarning that the person is likely to break down, although this disorder is more common in people with a pre-existing personality disorder. Paranoid personality disorder is characterised by an exaggeration of the cognitive modules for sensitivity to rejection, resentfulness, distrust, as well as the inclination to distort experienced events. Neutral and friendly actions of others are often misinterpreted as being hostile or contemptuous. Unfounded suspicions regarding the sexual loyalty of partners and loyalty in general as well as the belief that one's rights are not being recognized is stubbornly and argumentatively insisted upon. Such individuals can possess an excessive self-assurance and a tendency toward an exaggerated self reference. Pathological jealousy, instinctive aggressive counter-attack, the need to control others, and the gathering of trivial or circumstantial “evidence” to support their jealous beliefs also features.
Schizoid personality disorder (SPD) is characterised by a lack of interest in social relationships, a tendency towards a solitary lifestyle, secretiveness, and emotional coldness. SPD is reasonably rare compared with other personality disorders, its prevalence is estimated at less than 1% of the general population. Schizotypal personality disorder, is characterized by a need for social isolation, odd behaviour and thinking, and often unconventional beliefs such as being convinced of having extra-sensory abilities.
Psychosis and psychotic disorders are commonly treated with a class of medication known as atypical antipsychotics.
Anxiety disorders are a group of mental disorders characterized by feelings of anxiety and fear. Anxiety is a worry about future events and fear is a reaction to current events. These feelings may cause physical symptoms, such as a fast heart rate and shakiness. There are a number of anxiety disorders: including generalized anxiety disorder, specific phobia, social anxiety disorder, separation anxiety disorder, agoraphobia, and panic disorder. The disorder differs by what results in the symptoms. People often have more than one anxiety disorder.
The diagnosis of anxiety disorders is difficult because there are no objective biomarkers, it is based on symptoms, which typically need to be present at least six months, be more than would be expected for the situation, and decrease functioning. Several generic anxiety questionnaires can be used to detect anxiety symptoms, such as the State-Trait Anxiety Inventory (STAI), the Generalized Anxiety Disorder 7 (GAD-7), the Beck Anxiety Inventory (BAI), the Zung Self-Rating Anxiety Scale, and the Taylor Manifest Anxiety Scale. Other questionnaires combine anxiety and depression measurement, such as the Hamilton Anxiety Rating Scale, the Hospital Anxiety and Depression Scale (HADS), the Patient Health Questionnaire (PHQ), and the Patient-Reported Outcomes Measurement Information System (PROMIS). Examples of specific anxiety questionnaires include the Liebowitz Social Anxiety Scale (LSAS), the Social Interaction Anxiety Scale (SIAS), the Social Phobia Inventory (SPIN), the Social Phobia Scale (SPS), and the Social Anxiety Questionnaire (SAQ-A30).
Agoraphobia is an anxiety disorder characterized by symptoms of anxiety in situations where the person perceives the environment to be unsafe with no easy way to get away. These situations can include open spaces, public transit, shopping malls, or simply being outside the home. Being in these situations may result in a panic attack. The symptoms occur nearly every time the situation is encountered and lasts for more than six months. Those affected will go to great lengths to avoid these situations. In severe cases people may become unable to leave their homes.
Most people who present to mental health specialists develop agoraphobia after the onset of panic disorder. Agoraphobia is best understood as an adverse behavioral outcome of repeated panic attacks and subsequent anxiety and preoccupation with these attacks that leads to an avoidance of situations where a panic attack could occur. Early treatment of panic disorder can often prevent agoraphobia. Agoraphobia is typically determined when symptoms are worse than panic disorder, but also do not meet the criteria for other anxiety disorders such as depression. In rare cases where agoraphobics do not meet the criteria used to diagnose panic disorder, the formal diagnosis of agoraphobia without history of panic disorder is used (primary agoraphobia).
Attention deficit hyperactivity disorder (ADHD) is a mental disorder of the neurodevelopmental type. It is characterized by problems paying attention, excessive activity, or difficulty controlling behavior which is not appropriate for a person's age. These symptoms begin by age six to twelve, are present for more than six months, and cause problems in at least two settings (such as school, home, or recreational activities). ADHD often persists into adulthood, with resultant impairments of social, academic and occupational functioning. In children, problems paying attention may result in poor school performance. Although it causes impairment, particularly in modern society, many children with ADHD have a good attention span for tasks they find interesting.
ADHD is diagnosed by an assessment of a person's childhood behavioral and mental development, including ruling out the effects of drugs, medications and other medical or psychiatric problems as explanations for the symptoms. It often takes into account feedback from parents and teachers with most diagnoses begun after a teacher raises concerns. It may be viewed as the extreme end of one or more continuous human traits found in all people. Whether someone responds to medications does not confirm or rule out the diagnosis. As imaging studies of the brain do not give consistent results between individuals, they are only used for research purposes and not diagnosis.
In North America, DSM-5 criteria are used for diagnosis, while European countries usually use the ICD-10. With the DSM-IV criteria a diagnosis of ADHD is 3-4 times more likely than with the ICD-10 criteria. It is classified as neurodevelopmental psychiatric disorder. Additionally, it is classified as a disruptive behavior disorder along with oppositional defiant disorder, conduct disorder, and antisocial personality disorder. A diagnosis does not imply a neurological disorder.
Premenstrual dysphoric disorder (PMDD) is a severe and disabling form of premenstrual syndrome affecting 3-8% of menstruating women. The disorder consists of a “cluster of affective, behavioral and somatic symptoms” that recur monthly during the luteal phase of the menstrual cycle. PMDD was added to the list of depressive disorders in the Diagnostic and Statistical Manual of Mental Disorders in 2013. Authoritative diagnostic criteria for PMDD are provided by a number of expert medical guides, notably the Diagnostic and Statistical Manual of Mental Disorders V (DSM-V). The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), established seven criteria (A through G) for the diagnosis of PMDD.
Premenstrual syndrome (PMS) refers to physical and emotional symptoms that occur in the one to two weeks before a woman's period. Symptoms often vary between women and resolve around the start of bleeding. Common symptoms include acne, tender breasts, bloating, feeling tired, irritability, and mood changes. Often symptoms are present for around six days. A woman's pattern of symptoms may change over time. Symptoms do not occur during pregnancy or following menopause.
Huntington's disease (HD), also known as Huntington's chorea, is an inherited disorder that results in death of brain cells. The earliest symptoms are often subtle problems with mood or mental abilities. A general lack of coordination and an unsteady gait often follow. As the disease advances, uncoordinated, jerky body movements become more apparent. Physical abilities gradually worsen until coordinated movement becomes difficult and the person is unable to talk. Mental abilities generally decline into dementia. The specific symptoms vary somewhat between people. Symptoms usually begin between 30 and 50 years of age, but can start at any age. The disease may develop earlier in life in each successive generation. About 8% of cases start before the age of 20 years and typically present with symptoms more similar to Parkinson's disease. People with HD often underestimate the degree of their problems.
Medical diagnosis of the onset of HD can be made following the appearance of physical symptoms specific to the disease. Genetic testing can be used to confirm a physical diagnosis if there is no family history of HD. Even before the onset of symptoms, genetic testing can confirm if an individual or embryo carries an expanded copy of the trinucleotide repeat in the HTT gene that causes the disease. Genetic counseling is available to provide advice and guidance throughout the testing procedure, and on the implications of a confirmed diagnosis. These implications include the impact on an individual's psychology, career, family planning decisions, relatives and relationships. Despite the availability of pre-symptomatic testing, only 5% of those at risk of inheriting HD choose to do so.
Alzheimer's disease (AD), also known as just Alzheimer's, is a chronic neurodegenerative disease that usually starts slowly and gets worse over time. It is the cause of 60% to 70% of cases of dementia. The most common early symptom is difficulty in remembering recent events (short-term memory loss). As the disease advances, symptoms can include problems with language, disorientation (including easily getting lost), mood swings, loss of motivation, not managing self care, and behavioural issues. As a person's condition declines, they often withdraw from family and society. Gradually, bodily functions are lost, ultimately leading to death. Although the speed of progression can vary, the average life expectancy following diagnosis is three to nine years.
Alzheimer's disease is usually diagnosed based on the person's medical history, history from relatives, and behavioural observations. The presence of characteristic neurological and neuropsychological features and the absence of alternative conditions is supportive.
Parkinson's disease (PD) is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms generally come on slowly over time. Early in the disease, the most obvious are shaking, rigidity, slowness of movement, and difficulty with walking. Thinking and behavioral problems may also occur. Dementia becomes common in the advanced stages of the disease. Depression and anxiety are also common occurring in more than a third of people with PD. Other symptoms include sensory, sleep, and emotional problems. The main motor symptoms are collectively called “parkinsonism”, or a “parkinsonian syndrome”. A physician will diagnose Parkinson's disease from the medical history and a neurological examination.
An autoimmune disease is a condition arising from an abnormal immune response to a normal body part. There are at least 80 types of autoimmune diseases. Nearly any body part can be involved. Common symptoms include low grade fever and feeling tired. Often symptoms come and go.
There is a significant requirement for an effective treatment that is able to prevent or treat the above-discussed psychological and brain disorders without resulting in side-effects.